biogas upgrading system

Dutch company, Ecofuels, wanted to turn biogas from organic waste into a sustainable energy source. With Pentair Biogas Upgrading Solutions, Ecofuels realized their ambition.

THE STORY OF ECOFUELS
Founded in 2006, Ecofuels is an industrial, biochemical production company, originally initiated by Dutch company Laarakker Groenteverwerking B.V., a specialist in cultivating, processing and selling vegetables, and Indaver Nederland B.V., an industrial and household waste specialist.

Laarakker Groenteverwerking grows 110,000 tons of vegetables annually on 3,500 hectares (8,650 acres) and sells them to producers of canned, frozen and juice products. Indaver Nederland is a vegetable waste management specialist that processes 400,000 tons of vegetable waste to compost each year which is sold as fertilizer to agricultural and gardening enterprises. In 2006, Ecofuels started two biogas fermenters at its premises in Well, Limburg, The Netherlands. 120.000 tons of vegetable-based material is used as a substrate to produce the biogas, which is then converted into on-site electricity. Part of this substrate comes from Laarakker’s vegetable production and the rest from external suppliers.

Sustainable resource management and renewable energy are integral parts of Ecofuels’ philosophy. In 2011, Ecofuels decided to go one step further by expanding the capacity of their existing digesters to produce 650-700 m³  of biogas per hour. They wanted to start converting this biogas into biomethane, which is compatible for use in the national grid network due to its near-pure methane composition.

When seeking a biogas upgrading partner, Ecofuels opted for Pentair Biogas Upgrading System, Pentair BioComplete. The Biogas Upgrading System offers two distinct advantages:

∙ It provides a comprehensive approach for turning waste streams into sustainable energy solutions.
∙ The by-product, liquid CO₂, can be used as a commercially viable product rather than released into the atmosphere.

Pentair BioComplete splits Ecofuels’ biogas into a methane stream and a CO₂ off-gas stream. The raw biogas first goes through a scrubber and an activated carbon filter to remove impurities. Then a compressor provides the pressure needed to push the biogas through the membrane unit, where the primary separation process occurs. The off gas from the first membrane step goes to the CO₂ recovery plant, which is pressurized to 17.5 bar and cleaned in an activated carbon filter/dryer. The gas is stripped and liquefied by cooling to -24°C, while methane is fed back to the membrane unit.

The Pentair BioComplete plant at Ecofuels comprises of membrane and cryogenic technology. It produces 650-700 Nm3 /h of biogas which is processed into 340-360 Nm3 /h of biomethane or 2.800.000 m3 of biomethane per year 2 . Furthermore, 2.000 tons of renewable liquid CO2 are recovered per year.

THE FUTURE FOR ECOFUELS 

The resulting biomethane is fed into the national grid. Ecofuels receives the feed-in remuneration that is prescribed in the Dutch Renewable Energy Regulation. The CO₂ by-product is used across a variety of applications such as gaseous fertilizer in greenhouses, as a cooling agent in industrial applications and to produce dry ice which Ecofuels can use as an additional revenue stream